Prognostics-based risk mitigation for telecom equipment under free air cooling conditions

2012 ◽  
Vol 99 ◽  
pp. 423-429 ◽  
Author(s):  
Jun Dai ◽  
Diganta Das ◽  
Michael Pecht
Keyword(s):  
Risk Mitigation ◽  
Air Cooling ◽  
Cooling Conditions ◽  
Free Air

Reliability risk mitigation of free air cooling through prognostics and health management

2013 ◽  
Vol 111 ◽  
pp. 104-112 ◽  
Author(s):  
Jun Dai ◽  
Diganta Das ◽  
Michael Ohadi ◽  
Michael Pecht
Keyword(s):  
Health Management ◽  
Risk Mitigation ◽  
Air Cooling ◽  
Prognostics And Health Management ◽  
Free Air

scholarly journals Optimization of two-stage cooling conditions for wire rod diameter 5.5–6.5 mm of low-carbon steel grades in order to ensure the required degree of descaling mechanically before its subsequent processing

2018 ◽  
pp. 63-66
Author(s):  
V. V. Savinkov ◽  
I. A. Kovaleva
Keyword(s):  
Carbon Steel ◽  
Low Carbon Steel ◽  
Air Cooling ◽  
Low Carbon ◽  
Optimal Thickness ◽  
Wire Rod ◽  
Mechanical Removal ◽  
Cooling Conditions ◽  
Steel Grades ◽  
The Wire

With the aim of obtaining scale with a high degree possibility of mechanical removal under the conditions of the section rolling shop No. 1, at the mill «150» JSC «Belarusian Metallurgical Works – Management Company of Holding «BMC» developed technological modes of production of wire rods made of low-carbon steel grades.The peculiarities of scale formation were studied, namely, the factors influencing the removability, obtaining the optimal thickness and its phase components on the wire rod diameter 5.5–6.5 mm in the cooling process immediately after rolling, intended for wire production.To obtain the necessary ratio of the phase constituents of the scales on the surface of the wire rod, the following factors was taken into account: the temperature of the layout of the turns on the roller table in the air cooling line; (uniformity along the length of the turn), the cooling conditions of the helix of the turns (prevention of the 4FeO = Fe3O4-Fe decay), where the condition of cooling the wire rod from 600 to 250 °С, not exceeding 100 s, must be observed.The results of metallographic studies of scale on the wire surface are presented. The introduced technological regimes provided the optimal thickness and the FeO / Fe3O4 ratio after the experimental rolling of the metal. Exhausted cooling regimes allowed to reduce the consumption of fiber for all types of wire.

Tribological performance of industrial polyamide-imide and its composite under different cooling conditions

2012 ◽  
Vol 32 (3) ◽  
Author(s):  
Huseyin Unal ◽  
Mehmet Kurt ◽  
Abdullah Mimaroglu
Keyword(s):  
Friction And Wear ◽  
Air Cooling ◽  
Atmospheric Conditions ◽  
Insulation Property ◽  
Wear Rates ◽  
Cooling Conditions ◽  
316 L Stainless Steel ◽  
The Coefficient Of Friction ◽  
Steel Disc ◽  
Aisi 316 L

Abstract Polyamide-imide (PAI) polymer is a high-temperature resistant polymer, which is used as contact breaker material because of its high electrical insulation property. The working conditions of contact breakers arise from the wear and friction problem conditions of these materials. Therefore, the tribological behavior of PAI polymer is important. In this study, the friction and wear performance of pure PAI polymer and PAI composite [PAI+12% graphite+3% polytetrafluoroethylene (PTFE)] were studied in two different cooling environmental conditions (with and without air cooling). Wear tests were carried out with the configuration of a polymer pin, on a rotating AISI 316 L stainless steel disc. Test conditions were atmospheric conditions, 50 N, 100 N, and 150 N loads and 0.5, 1.0, 2.0 and 3.0 m/s sliding speeds. For sliding without air cooling and sliding with air cooling, the results show that the coefficient of friction and wear rates for pure PAI and PAI+12% graphite+3% PTFE composite, slightly decrease and increase with the increase in applied load and sliding speed values, respectively. In addition, for the range of loads and sliding speeds of this study, low coefficients of friction and high specific wear rates are registered at sliding under air cooling conditions. Finally, the wear mechanism includes adhesive and abrasive processes.

scholarly journals Effect of heat treatment on the microstructure, hardness and abrasive wear resistance of high chromium hardfacing

2013 ◽  
Vol 59 (No. 1) ◽  
pp. 23-28 ◽  
Author(s):  
R. Chotěborský
Keyword(s):  
Heat Treatment ◽  
Fracture Toughness ◽  
Wear Resistance ◽  
Abrasive Wear ◽  
Abrasive Wear Resistance ◽  
Air Cooling ◽  
High Chromium ◽  
Secondary Carbides ◽  
Cooling Conditions ◽  
Dendritic Austenite

The effect of destabilization heat treatment on the microstructure, hardness, fracture toughness and abrasive wear resistance of high chromium hardfacing was investigated. The results from the study shows that the hardness, frac­ture toughness and abrasive wear resistance are influenced by temperature of destabilization heat treatment and air and furnace cooling conditions, respectively. Destabilization treatment of materials by furnace cooling caused higher secondary carbides in the dendritic austenite whilst by air cooling it showed smaller particles of secondary carbide. Also, it was found that destabilization temperature at 1,000°C improves hardness compared with hardfacing after weld depositing. The study, however, indicated that Palmqvist fracture toughness method is a useful technique for measuring the fracture toughness of high chromium hardfacing compared to Vicker’s hardness method.    

Air Flow Pattern and Path Flow Simulation of Airborne Particulate Contaminants in a High-Density Data Center Utilizing Airside Economization

2018 ◽  
Author(s):  
Gautham Thirunavakkarasu ◽  
Satyam Saini ◽  
Jimil Shah ◽  
Dereje Agonafer
Keyword(s):  
Data Center ◽  
Carbon Particle ◽  
High Density ◽  
Submicron Particles ◽  
Air Cooling ◽  
Density Data ◽  
Particulate Contamination ◽  
Free Air ◽  
First Choice ◽  
Particulate Contaminants

The percentage of the energy used by data centers for cooling their equipment has been on the rise. With that, there has been a necessity for exploring new and more efficient methods like airside economization, both from an engineering as well as business point of view, to contain this energy demand. Air cooling especially, free air cooling has always been the first choice for IT companies to cool their equipment. But, it has its downside as well. As per ASHRAE standard (2009b), the air which is entering the data center should be continuously filtered with MERV 11 or preferably MERV 13 filters and the air which is inside the data center should be clean as per ISO class 8. The objective of this study is to design a model data center and simulate the flow path with the help of 6sigma room analysis software. A high-density data center was modelled for both hot aisle and cold aisle containment configurations. The particles taken into consideration for modelling were spherical in shape and of diameters 0.05, 0.1 and 1 micron. The physical properties of the submicron particles have been assumed to be same as that of air. For heavier particles of 1 micron in size, the properties of dense carbon particle are chosen for simulating particulate contamination in a data center. The Computer Room Air Conditioning unit is modelled as the source for the particulate contaminants which represents contaminants entering along with free air through an air-side economizer. The data obtained from this analysis can be helpful in predicting which type of particles will be deposited at what location based on its distance from the source and weight of the particles. This can further help in reinforcing the regions with a potential to fail under particulate contamination.

Experimental Description of Information Technology Equipment Reliability Exposed to a Data Center Using Airside Economizer Operating in Recommended and Allowable ASHRAE Envelopes in an ANSI/ISA Classified G2 Environment

2020 ◽  
Vol 142 (2) ◽  
Author(s):  
Oluwaseun Awe ◽  
Jimil M. Shah ◽  
Dereje Agonafer ◽  
Prabjit Singh ◽  
Naveen Kannan ◽  
...  
Keyword(s):  
Information Technology ◽  
Data Center ◽  
Data Centers ◽  
Operating Cost ◽  
Weather Data ◽  
Air Cooling ◽  
Single Server ◽  
Severity Level ◽  
Equipment Reliability ◽  
Free Air

Abstract Airside economizers lower the operating cost of data centers by reducing or eliminating mechanical cooling. It, however, increases the risk of reliability degradation of information technology (IT) equipment due to contaminants. IT Equipment manufacturers have tested equipment performance and guarantee the reliability of their equipment in environments within ISA 71.04-2013 severity level G1 and the ASHRAE recommended temperature-relative humidity (RH) envelope. IT Equipment manufacturers require data center operators to meet all the specified conditions consistently before fulfilling warranty on equipment failure. To determine the reliability of electronic hardware in higher severity conditions, field data obtained from real data centers are required. In this study, a corrosion classification coupon experiment as per ISA 71.04-2013 was performed to determine the severity level of a research data center (RDC) located in an industrial area of hot and humid Dallas. The temperature-RH excursions were analyzed based on time series and weather data bin analysis using trend data for the duration of operation. After some period, a failure was recorded on two power distribution units (PDUs) located in the hot aisle. The damaged hardware and other hardware were evaluated, and cumulative corrosion damage study was carried out. The hypothetical estimation of the end of life of components is provided to determine free air-cooling hours for the site. There was no failure of even a single server operated with fresh air-cooling shows that using evaporative/free air cooling is not detrimental to IT equipment reliability. This study, however, must be repeated in other geographical locations to determine if the contamination effect is location dependent.

Solidification Simulation of Large Flat Ingot in Different Intensive Cooling Conditions

2012 ◽  
Vol 430-432 ◽  
pp. 517-520
Author(s):  
Nan Lv ◽  
Sheng Li Li ◽  
Yong Long Jin ◽  
Xin Gang Ai ◽  
Dong Wei Zhang
Keyword(s):  
Shrinkage Cavity ◽  
Air Cooling ◽  
Water Cooling ◽  
Columnar Crystal ◽  
Heavy Plate ◽  
Fine Grain ◽  
Solidification Simulation ◽  
Cooling Conditions ◽  
Forced Air ◽  
Shrinkage Cavities

The production of huge rectangular ingots becomes crying needs in the condition of lots of heavy plate mills more than 5m have been in operation. In this paper, we simulate the solidification of 60t Q235 huge rectangular ingot with ProCAST in different cooling conditions such as air cooling, forced air cooling and water cooling. The results show that solidification time in forced air cooling and water cooling shortened than that in air cooling respectively by 0.9 hours and 2.2 hours; The primary fine-grain area is large in the forced air cooling and water cooling. In forced air cooling , we can obtain the largest equiaxial crystal ratio and the minimum columnar crystal ratio; The shrinkage cavity position of the ingot in forced air cooling and water cooling is closer to riser than it is in air cooling, but the volumes of shrinkage cavities respectively increased to a greater extent than in air cooling.

Thermal Analysis of Li-ion Battery

2013 ◽  
Vol 401-403 ◽  
pp. 450-455
Author(s):  
Gaoussou Hadia Fofana ◽  
You Tong Zhang
Keyword(s):  
Thermal Behavior ◽  
Thermal Model ◽  
Air Cooling ◽  
Li Ion Battery ◽  
Battery System ◽  
Cooling Conditions ◽  
3D Fea ◽  
Li Ion ◽  
Prismatic Cell ◽  
Battery Cells

Abstract. The paper has built 3D-FEA models to simulate the electro-thermal behavior of Li-ion battery cells with Pouch Cell and Prismatic Cell by ANSYS. As for two models, the Li-ion battery system is simplified as a single equivalent battery layer (Pouch Cell) or multiple equivalent battery layers (Prismatic Cell) with the equivalent electrodes and separator. They were simulated under air cooling conditions. Simulations were compared with available battery temperature measurements. This shows that the 3D electro-thermal model applied in this study characterizes the electro-thermal behavior of the Li-ion battery cells reasonably well.

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